That is what I read as well, but if the window is this small going out to get tested is really useless to determine who has be exposed especially with Omicron. Just kind of odd IMO.Mmm that's more or less how the rapid antigen tests are supposed to function. You test positive when you're contagious. Not when symptoms begin. You test negative when you're no longer contagious even they you might still be symptomatic.
Check out Michael Mina on Twitter as he has thousands of tweets on exactly how the tests should function.